The European Space Agency's Huygens probe recently returned from Titan, one of Saturn's moons. Scientists deduced that the moon contained large amounts of liquid methane just below the surface. This suprised scientists who expected to see higher amounts of ethane due to the photochemical processes that change methane into ethane. It is also intersting to note how cold the moon is because there the methane gas exists at -180°C. Many questions still remain about the chemistry of methane on Titan and there is believed to be a source of methane inside Titan.(Mitchell K.) http://pubs.acs.org/cen/news/83/i04/8304titan.html